In the earliest days of Egypt, over four thousand years ago, there were two kingdoms: Upper Egypt and Lower Egypt. When these came together under one king Ancient Egypt became one of the most powerful empires in the world.
During the time of the New Kingdom, which was when kings (pharaohs) like Tutenkhamun were on the throne, Egypt had great cities from the Nile delta in the north, to Thebes in the south. Thebes was in Upper Egypt.
While many of the great cities and temples in Lower Egypt have been lost, the great temples at Thebes still stand, albeit in ruins. They are one of the most important tourist sites in the world.